On 10/25/2018 02:37 PM, Michael Mueller wrote:
> The GIB (Guest Information Block) links the GISA of all guests
> that have adapter interrupts pending. These interrupts cannot be
> deliverd because no vcpu of these guests is currently running in
> SIE context. Instead, a GIB alert is issued on the host to schedule
> these guests to run.
>
> This mechanism allows to process adapter interrupts for currently
> not running guests.
>
> The GIB is created during host initialization and associated with
> the Adapter Interruption Facility in case an Adapter Interruption
> Virtualization Facility is available.
>
> Signed-off-by: Michael Mueller <mimu@xxxxxxxxxxxxx>
Some small nits below.
Other than that
Reviewed-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
> ---
> arch/s390/include/asm/kvm_host.h | 10 ++++++++
> arch/s390/kvm/interrupt.c | 43 ++++++++++++++++++++++++++++++++
> arch/s390/kvm/kvm-s390.c | 1 +
> arch/s390/kvm/kvm-s390.h | 2 ++
> 4 files changed, 56 insertions(+)
>
> diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
> index 29c940bf8506..01be3b666b11 100644
> --- a/arch/s390/include/asm/kvm_host.h
> +++ b/arch/s390/include/asm/kvm_host.h
> @@ -776,6 +776,15 @@ struct kvm_s390_gisa {
> };
> };
>
> +struct kvm_s390_gib {
> + atomic_t alert_list_origin;
The only place that touches this is patch 5 (setting it to 0). All other activities
are done by HW and that is why we need an atomic update.
atomic_t does work as of today but you never know if we add some debugging code in the
future that makes atomic_t bigger. Can we maybe just use an u32 here and then use cmpxchg
in patch5?
> + u32 reserved01;
> + u8:5;
> + u8 nisc:3;
> + u8 reserved03[3];
> + u32 reserved04[5];
> +};
> +
> /*
> * sie_page2 has to be allocated as DMA because fac_list, crycb and
> * gisa need 31bit addresses in the sie control block.
> @@ -829,6 +838,7 @@ struct kvm_arch{
> /* subset of available cpu features enabled by user space */
> DECLARE_BITMAP(cpu_feat, KVM_S390_VM_CPU_FEAT_NR_BITS);
> struct kvm_s390_gisa *gisa;
> + int gib_in_use;
> };
i>
> #define KVM_HVA_ERR_BAD (-1UL)
> diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
> index fcb55b02990e..3789a9ad8dee 100644
> --- a/arch/s390/kvm/interrupt.c
> +++ b/arch/s390/kvm/interrupt.c
> @@ -31,6 +31,8 @@
> #define PFAULT_DONE 0x0680
> #define VIRTIO_PARAM 0x0d00
>
> +static struct kvm_s390_gib *gib;
> +
> /* handle external calls via sigp interpretation facility */
> static int sca_ext_call_pending(struct kvm_vcpu *vcpu, int *src_id)
> {
> @@ -2899,6 +2901,7 @@ void kvm_s390_gisa_init(struct kvm *kvm)
> kvm->arch.gisa = &kvm->arch.sie_page2->gisa;
> VM_EVENT(kvm, 3, "gisa 0x%pK initialized", kvm->arch.gisa);
> kvm_s390_gisa_clear(kvm);
> + kvm->arch.gib_in_use = !!gib;
> }
> }
>
> @@ -2908,3 +2911,43 @@ void kvm_s390_gisa_destroy(struct kvm *kvm)
> return;
> kvm->arch.gisa = NULL;
> }
> +
> +void kvm_s390_gib_destroy(void)
> +{
> + if (!gib)
> + return;
> + chsc_sgib(0);
> + free_page((unsigned long)gib);
> + gib = NULL;
> +}
> +
> +void kvm_s390_gib_init(u8 nisc)
> +{
> + int rc;
> +
> + if (gib)
> + return;
> +
> + if (!css_general_characteristics.aiv) {
> + KVM_EVENT(3, "%s", "gib not initialized, no AIV facility");
> + return;
> + }
> +
> + gib = (struct kvm_s390_gib *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
> + if (!gib) {
> + KVM_EVENT(3, "%s", "gib memory allocation failed");
> + return;
> + }
> +
> + gib->nisc = nisc;
> + rc = chsc_sgib((u32)(u64)gib);
> + if (rc) {
You could get rid of rc by doing
if (chsc_sgib((u32)(u64)gib))
> + KVM_EVENT(3, "gib 0x%pK AIV association failed rc: %d",
> + gib, rc);
> + free_page((unsigned long)gib);
> + gib = NULL;
> + return;
> + }
> +
> + KVM_EVENT(3, "gib 0x%pK (nisc=%d) initialized", gib, gib->nisc);
> +}
[...]
